IFC Export options settings (AECOsim BD)

Can someone explain what the options below are for in the IFC export dialog box.  The help file isnt detailed enough.

 

Comment TAB

Project. - This seeems to want to point to a file, but what file and where.  What purpose is it?

Building - As above

Site - As above

Or is this just simple text that relates to the file your exporting?